This multicenter, open-label long-term extension study evaluates long-term chol-esterol lowering effectiveness, safety and tolerability of DMP 504 in patients with primary hypercholesterolemia who have completed a short-term Phase II/III study without regard to treatment received in the short-term study. The study mimics the anticipated clinical management of patients with hypercholesterolemia by allowing investigators to adjust DMP 504 doses and to employ add-on therapies (combination treatment).